Artworks on paper, pin holes,defaults, stains etc.
Artworks exposed to ultraviolet rays can be severely damaged. The paper can show yellowing or darken, even the artwork itself can be affected by altering the brilliance by example of the colors. It is advised to reduce the effect of ultraviolet rays by using Plexiglas or ultraviolet resistant glass.
Small red/brown or even black spots are called foxing. It depends often on the quality of the paper itself. Under humidity the small impurities in the paper have a chemical reaction leaving these small stains.
When artists working on paper supports use tick layers of gouache or tempera this may result in cracks in the paint itself, these cracks are named “craquelure”
Most of supports we use for works on paper are acid-free. This practice is only done since a couple decades, older works on paper came in contact with boards and paper not acid free. This could affect the artwork itself, even destroy the artwork on paper.
Pin holes usually at the corner of artworks An artist may pin down a sheet of paper to a support. For an original artwork it will not have an impact on the value of the artwork. If this is done to a lithograph by the owner of a lithograph by example to pin it to the wall it will decrease the value of the lithograph with at least 35 %.
An artwork on paper is attached to a support mat or a board, by hinging or mounting the artwork If it is hinged on the upper side only it can be analyzed on the back by lifting the artwork. Sometimes you have signature, information related to the artwork, a date of execution etc. mentioned on the back. Usually the paper artworks are mounted on the four sides so that they can’t be moved.